Apparatus and method for forming inflated chambers

ABSTRACT

An inflatable web, and method and apparatus for inflating the web, which generally includes two sheets having inner surfaces sealed to each other in a pattern defining a series of inflatable chambers of predetermined length, each of the chambers having at least one change in width over their length; an inflation port located at a proximal end of each chamber, the inflation ports being formed by intermittent seals between the sheets; and longitudinal flanges formed by a portion of each of the sheets that extend beyond the inflation ports and intermittent seals.

[0001] This Application claims the benefit from U.S. ProvisionalApplication No. 60/290,161, filed May 10, 2001.

BACKGROUND OF THE INVENTION

[0002] This invention relates to inflatable webs that can be inflated toprovide gas inflated cushioning for protective packaging applications.More particularly, this invention relates to improved inflatable websand apparatus and process for inflating the inventive webs to providegas inflated air cellular cushioning.

[0003] Air cellular cushioning materials are commonly used to protectarticles during shipment. One such product is Bubble Wrap® air cellularcushioning sold by Sealed Air Corp. Air cellular cushioning is generallyprepared at a production plant and shipped in rolls to distributors andend users. Since the rolls are bulky and have a large volume to weightratio, shipping costs are relatively high. In addition, the large volumeto weight ratio means that relatively large storage areas may berequired for storing inventoried cushioning.

[0004] To address these issues, it has been proposed to provideinflatable webs shipped to an end user in a roll having a relatively lowvolume to weight ratio. The end user would then inflate the roll asneeded. In general, such products have not been commercially significantbecause of the cost, complexity and reliability of the inflationequipment that is required or because of the complexity of the attendantinflation processes and techniques. These problems have, in turn,resulted in inconsistent inflation or difficulty in controlling thedegree of inflation.

[0005] This invention provides inflatable webs that can be reliably andconsistently inflated by end users to provide desired air cellularcushioning. The invention further provides a simplified apparatusadapted for inflation of the webs of the invention and an attendantsimplified inflation method.

SUMMARY OF THE INVENTION

[0006] One aspect of the present invention is an inflatable web,comprising:

[0007] a) two sheets having inner surfaces sealed to each other in apattern defining a series of inflatable chambers of predeterminedlength, each of the chambers having at least one change in width overtheir length;

[0008] b) an inflation port located at a proximal end of each chamber,the inflation ports being formed by intermittent seals between thesheets; and

[0009] c) longitudinal flanges formed by a portion of each of the sheetsthat extend beyond the inflation ports and intermittent seals.

[0010] Another aspect of the invention pertains to a method of formingan inflated cushioning product, the method comprising the steps of:

[0011] a) providing an inflatable web as described above;

[0012] b) placing an inflation nozzle between the longitudinal flanges,the nozzle comprising a gas outlet port for injection of gas into theinflatable chambers;

[0013] c) moving the web and inflation nozzle relative to each other soas to cause the inflation nozzle to move longitudinally between theflanges;

[0014] d) inflating the series of chambers sequentially by theintroduction of a gas into their respective inflation ports; and

[0015] e) sealing the inflation port of each inflated chamber.

[0016] A further aspect of the invention is directed to an apparatus forinflating a web, comprising:

[0017] a) a mechanism for conveying the above-described inflatable webalong a path of travel;

[0018] b) an inflation nozzle within the travel path and positioned forplacement between the longitudinal flanges of the web, the inflationnozzle comprising a gas outlet port for injection of gas into theinflatable chambers and being adapted to position the gas outlet portclosely adjacent to the inflation ports and intermittent seals so that,as the conveying mechanism conveys the web along the travel path, theinflation nozzle moves longitudinally between the flanges to inflate theseries of chambers sequentially by the introduction of gas into theirrespective inflation ports; and

[0019] c) a device for sealing the inflation ports.

[0020] These and other aspects and features of the invention may bebetter understood with reference to the following description andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

[0021]FIG. 1 is a plan view of an inflatable web of the invention.

[0022]FIG. 2 is a side elevational view of an apparatus of theinvention.

[0023]FIG. 3 is a partial front view of the apparatus shown in FIG. 2.

[0024]FIG. 4 is a perspective view of the apparatus shown in FIGS. 2 and3, further showing the positioning of a nozzle for inflation of a web asshown in FIG. 1.

[0025]FIG. 5 is a partial cross-sectional view taken along lines 5-5 inFIG. 3.

[0026]FIG. 6 is a partial cross-sectional view similar to that shown inFIG. 5, further showing the inflation nozzle moving to an adjacentinflation port of the web to begin inflation of the associated chamber.

[0027]FIG. 7 is a plan view of an inflated web of the invention showingthe positioning of heat seals formed after inflation.

DETAILED DESCRIPTION OF THE INVENTION

[0028] Referring to FIG. 1, there is shown an inflatable web 10 inaccordance with the present invention, comprising two sheets 12 and 14having respective inner surfaces 12 a and 14 a sealed to each other in apattern defining a series of inflatable chambers 16 of predeterminedlength “L.” Length L may be substantially the same for each of thechambers 16, with adjacent chambers being off-set from one another asshown in order to arrange the chambers in close proximity to oneanother. Sheets 12 and 14 are sealed to each other in a pattern of seals18 that defines the inflatable chambers 16 such that each of thechambers has at least one change in width over their length L. That is,seals 18 may be patterned to provide in each chamber 16 a series ofsections 20 of relatively large width connected by relatively narrowpassageways 22. When inflated, sections 20 may provide essentiallyspherical bubbles in web 10 by symmetrical outward movement of thosesections of sheets 12 and 14 comprising the walls of sections 20. Thiswill generally occur when sheets 12 and 14 are identical in thickness,flexibility, and elasticity. Sheets 12 and 14 may, however, be ofdifferent thickness, flexibility or elasticity such that inflation willresult in different displacement of sheets 12 and 14, thereby providinghemispherical or asymmetrical bubbles.

[0029] Seals 18 are also patterned to provide inflation ports 24, whichare located at proximal end 26 of each of the inflatable chambers 16 inorder to provide access to each chamber so that the chambers may beinflated. Opposite to the proximal end 26 of each chamber is a closeddistal end 28. As shown, seals 18 at proximal end 26 are intermittent,with inflation ports 24 being formed therebetween. Preferably, inflationports 24 are narrower in width than the inflatable sections 20 ofrelatively large width in order to minimize the size of the sealrequired to close off each chamber 16 after inflation thereof.

[0030] Inflatable web 10 further includes a pair of longitudinal flanges30, which are formed by a portion of each of sheets 12 and 14 thatextend beyond inflation ports 24 and intermittent seals 18. In theembodiment shown in FIG. 1, flanges 30 extend out equally beyond ports24 and seals 18. The flanges accordingly have equivalent widths, shownas width “W.” Flanges 30, in conjunction with ports 24 and seals 18,constitute an open inflation zone in web 10 that is advantageouslyconfigured to provide rapid and reliable inflation of chambers 16. Asdiscussed in greater detail below, the inner surfaces of flanges 30preferably are brought into close slidable contact with outwardly facingsurfaces of an appropriately configured nozzle or other inflation meansso as to provide a partially closed inflation zone which promotesefficient and reliable sequential inflation of chambers 16 withoutrestricting the movement of the web or inflation nozzle that is requiredto effect this sequential inflation. Flanges 30 are preferably at least¼ inch in width and, more preferably, at least ½ inch in width. Theflanges may have different widths, but it is generally preferred thatthey are equal in width, as shown in FIG. 1.

[0031] Preferably, the seal pattern of seals 18 provides uninflatableplanar regions between chambers 16. These planar regions serve asflexible junctions that may advantageously be used to bend or conformthe inflated web about a product in order to provide optimal cushioningprotection. In another embodiment, the seal pattern can compriserelatively narrow seals that do not provide planar regions. These sealsserve as the common boundary between adjacent chambers. Such a sealpattern is shown for example in U.S. Pat. No. 4,551,379, the disclosureof which is incorporated herein by reference. The seals 18 may be heatseals between the inner surfaces of the sheets 12 and 14. Alternatively,sheets 12 and 14 may be adhesively bonded to each other. Heat seals arepreferred and, for brevity, the term “heat seal” is generally usedhereinafter. This term should be understood, however, to include theformation of seals 18 by adhesion of sheets 12 and 14 as well as by heatsealing. Preferably, sheets 12 and 14 comprise a thermoplastic heatsealable polymer on their inner surface such that, after superpositionof sheets 12 and 14, web 10 can be formed by passing the superposedsheets beneath a sealing roller having heated raised land areas thatcorrespond in shape to the desired pattern of seals 18. The sealingroller applies heat and forms seals 18 between sheets 12 and 14 in thedesired pattern, and thereby also forms chambers 16 with a desiredshape. The sealing pattern on the sealing roller also providesintermittent seals at proximal end 26, thus forming inflation ports 24and also effectively resulting in the formation of flanges 30. Furtherdetails concerning this manner of making web 10 are disclosed incommonly-assigned, copending patent application Ser. No. 09/934,732entitled INTEGRATED PROCESS FOR MAKING INFLATABLE ARTICLE (Kannankerilet al.), filed on Aug. 22, 2001, the disclosure of which is herebyincorporated herein by reference.

[0032] Heat sealability of sheets 12 and 14 can be provided by employinga monolayer sheet comprising a heat sealable polymer or a multilayersheet comprising an inner layer comprising a heat sealable polymer. Ineither case, inflation ports 24 preferably also comprise inner surfacesthat are heat sealable to one another to allow such ports to be closedby heat sealing means after inflation of a corresponding chamber (thisis described in further detail below).

[0033] Sheets 12 and 14 may initially be separate sheets that arebrought into superposition and sealed or they may be formed by folding asingle sheet onto itself with the heat sealable surface facing inward.The longitudinal edge opposite from flanges 30, shown as edge 32 in FIG.1, is closed. Closed edge 32 may be formed in the web as a result offolding a single sheet to form sheets 12 and 14, whereby the foldconstitutes edge 32, or by sealing individual sheets 12 and 14 in thevicinity of the longitudinal edge as part of the pattern of seals 18.Although this edge is shown as closed in FIG. 1, in other embodiments ofthe webs of this invention this edge may be open and comprise a pair offlanges similar to flanges 30 to provide a second open inflation zonefor inflating a second series of inflatable chambers or for inflation ofthe chambers from both ends.

[0034] Sheets 12, 14 may, in general, comprise any flexible materialthat can be manipulated to enclose a gas in chambers 16 as hereindescribed, including various thermoplastic materials, e.g., polyethylenehomopolymer or copolymer, polypropylene homopolymer or copolymer, etc.Non-limiting examples of suitable thermoplastic polymers includepolyethylene homopolymers, such as low density polyethylene (LDPE) andhigh density polyethylene (HDPE), and polyethylene copolymers such as,e.g., ionomers, EVA, EMA, heterogeneous (Zeigler-Natta catalyzed)ethylene/alpha-olefin copolymers, and homogeneous (metallocene,single-cite catalyzed) ethylene/alpha-olefin copolymers.Ethylene/alpha-olefin copolymers are copolymers of ethylene with one ormore comonomers selected from C₃ to C₂₀ alpha-olefins, such as 1-butene,1-pentene, 1-hexene, 1-octene, methyl pentene and the like, in which thepolymer molecules comprise long chains with relatively few side chainbranches, including linear low density polyethylene (LLDPE), linearmedium density polyethylene (LMDPE), very low density polyethylene(VLDPE), and ultra-low density polyethylene (ULDPE). Various othermaterials are also suitable such as, e.g., polypropylene homopolymer orpolypropylene copolymer (e.g., propylene/ethylene copolymer),polyesters, polystyrenes, polyamides, polycarbonates, etc. The film maybe monolayer or multilayer and can be made by any known coextrusionprocess by melting the component polymer(s) and extruding or coextrudingthem through one or more flat or annular dies.

[0035] Referring now to FIGS. 2-4, an apparatus 34 for inflating web 10will be described. Apparatus 34 includes a conveying mechanism,generally indicated at 36, an inflation nozzle 38, and a sealing device40. Conveying mechanism 36 conveys web 10 along a path of travel asshown, which allows inflation nozzle 38 to sequentially inflate each ofchambers 16 and sealing device 40 to seal closed the inflated chambers.The “path of travel” (or “travel path”) of web 10 refers to the routethat such web traverses while being conveyed through apparatus 34 inthis manner, as indicated by the shape assumed by the web as it ismanipulated by the conveying mechanism.

[0036] Conveying mechanism 36 may include a shaft 42 mounted to housing43, a pair of adjacent, counter-rotatable cylinders 44 and 46, and aguide roll 51. Web 10 is preferably provided in the form of a supplyroll 48, which may be wound on spool 50 and mounted on shaft 42. Web 10is advanced, i.e., unwound, from supply roll 48, with guide roll 51directing the web between cylinders 44, 46 in a substantially verticaldirection as shown. Cylinders 44, 46 are capable of engaging and movingweb 10 along its travel path through apparatus 34 when a portion of thefilm web passes between the cylinders and the cylinders rotate in thedirections indicated in FIG. 3 against the web. The counter-rotation ofthe cylinders against web 10 exerts sufficient force on web 10 to causerotation of supply roll 48, thus dispensing web 10 for travel throughapparatus 34 as shown. Preferably, at least one of cylinders 44, 46 hasan uneven surface, e.g., a knurled or abraded surface as shown in FIG.4, or a grooved or inwardly threaded surface. It is also preferred thatthe opposing cylinder, i.e., opposite the cylinder having an unevensurface, is formed from a relatively resilient or pliable material, suchas silicone or rubber, which may have grooves in the surface thereof.

[0037] One or both cylinders 44, 46 are preferably coupled to anelectrical, hydraulic, or pneumatic motor (not shown), having arotational output to cause the cylinders to rotate. For example a singlemotor, such as an electrical “gear head” motor, may be axially coupledto cylinder 44, which causes cylinder 44 to rotate when power (e.g.,electricity) is supplied to the motor. When cylinder 44 is positioned inabutting relationship with cylinder 46 as shown, the rotation ofcylinder 44 causes cylinder 46 to rotate. Alternatively, a motor couldbe coupled instead to cylinder 46 or, as a further alternative, separatedrive motors could be coupled to each of cylinders 44, 46.

[0038] Sealing device 40 is preferably positioned immediately downstreamfrom inflation nozzle 38, so that each chamber 16 may be sealed closedimmediately after being inflated and/or contemporaneous with inflation.The sealing device 40 preferably seals closed the inflation ports 24 ofeach chamber 16 by forming a continuous longitudinal seal 52 as shown.

[0039] A preferred sealing device is disclosed in commonly-assigned,copending patent application Ser. No. 09/760,105 entitled DEVICE FORSEALING IWO PLIES OF FILM TOGETHER, PARTICULARLY FOR ENCLOSING AFOAMABLE COMPOSITION IN A FLEXIBLE CONTAINER (Sperry et al.), filed onJan. 12, 2001 and bearing attorney docket number D-20084-01, thedisclosure of which is hereby incorporated herein by reference. Such asealing device, as perhaps best shown in FIG. 4 (wherein a portion ofweb 10 has been broken away for clarity), includes an electricallyconductive heating element 54 having a first end secured to a first node56 and a second end secured to a second node 58. Heating element 54 ispositioned between cylinders 44, 46 such that cylinder 44 rotatesagainst the heating element, which is stationary and fixed to platform60 via nodes 56 and 58. Cylinder 44 preferably includes acircumferential groove in which heating element 54 ‘rides’ as cylinder44 rotates against the heating element 54. Cylinder 46 also rotatesagainst the heating element, but only at the nip (point of tangentialcontact) between the cylinders.

[0040] The inflation port 24 of each inflatable chamber 16 is sealedclosed when conveying mechanism 36 brings web 10 into moving contactwith heating element 54 between cylinders 44, 46 and sufficient currentis caused to flow through the heating element that it (i.e., the heatingelement 54) heats to a sealing temperature sufficient to formlongitudinal heat seal 52 between juxtaposed 12, 14 of web 10. As notedabove, such sealing of inflation ports 24 occurs shortly after inflationof the chamber 16 associated with each port. In this manner, gas frominflation nozzle 38 is trapped, i.e., enclosed, within each chamber,resulting in the formation of inflated chambers 62.

[0041] When sheets 12, 14 of web 10 are formed from a thermoplasticfilm, the sealing temperature necessary to form longitudinal seal 52 isthat which causes the film sheets 12, 14 to weld or fuse together bybecoming temporarily fully or partially molten in the area of contactwith the heating element 54. Such temperature, i.e., the “sealingtemperature,” may readily be determined by those of ordinary skill inthe art without undue experimentation for a given application based on,e.g., the composition and thickness of the film sheets to be sealed, thespeed at which the film sheets move against the heating element, and thepressure at which the film sheets and heating element are urged togetherbetween cylinders 44, 46. As an example, when sheets 12, 14 comprisepolyethylene-based films ranging in thickness from about 0.001 to about0.003 inch (for a combined, juxtaposed thickness ranging from 0.002 to0.006 inch), the sealing temperature to which heating element 54 isheated preferably ranges from about 300 to about 500° F.

[0042] Heating element 54 may be any device capable of heating to apredetermined temperature sufficient to heat-seal sheets 12, 14together. Suitable types of devices for heating element 54 include oneor more wires comprising metal and/or other electrically conductivematerials; one or more ribbons comprising metal; circuit-printed plasticribbons, e.g., metal printed on a plastic substrate comprisingpolyethylene terephthalate (PET); and other suitable electricallyconductive devices.

[0043] The drawings illustrate heating element 54 in the form of a wire.When heating element 54 assumes such a form, the wire may have anydesired cross-sectional shape, including round, square, oval,rectangular, etc.

[0044] An alternative sealing device which may be used in the apparatus34 in accordance with the present invention employs a heating elementthat is completely wrapped about the outer circumference of a cylinder,as disclosed in U.S. Pat. No. 5,376,219, the disclosure of which isincorporated by reference herein. As a further alternative to employingthe sealing device 40 as described above, one or both sheets 12, 14 mayinclude strips of a bonding material located within inflation ports 24.Such a bonding material, e.g., an adhesive or cohesive material, forms aseal when sheets 12, 14 are pressed together between cylinders 44, 46.Further details concerning this means for sealing two film pliestogether are described in copending U.S. Ser. No. 09/591,830, filed Jun.12, 2000 and entitled METHOD FOR ENCLOSING A FOAMABLE COMPOSITION IN AFLEXIBLE BAG (Oberle et al.), the disclosure of which is herebyincorporated herein by reference.

[0045] The completed cushioning material 64, formed by a series ofinflated and sealed chambers 62, may be collected in a basket or othersuitable container as indicated at 66 in FIG. 2, until needed for use.If desired, web 10 may include one or more lines of weakness 68 thatallow sections “S” of predetermined length to be removed from web 10. Inthis manner, such sections S of completed cushioning material 64 may beremoved for individual use. Transverse lines of weakness 68 preferablycomprise a series of perforations as shown, and extend from closed edge32 to and through flanges 30. As an alternative to providing perforationlines 68, a severing device may be included to sever, e.g., viamechanical means and/or heat, sections of completed cushioning materialfrom the web, wherein such sections may have any desired length of fixedor variable dimension.

[0046] With continuing reference to FIGS. 2-4, and with additionalreference to FIGS. 5-6, the sequential inflation of chambers 16 will bedescribed in further detail. Inflation nozzle 38 is within the travelpath of web 10 and, specifically, is positioned for placement betweenthe longitudinal flanges 30 of web 10. This may be seen in FIGS. 4-6 (aportion of upper sheet 12 has been broken away for clarity in FIGS.5-6). As used herein with reference to web 10, the term “longitudinal”refers to the direction of conveyance of web 10 through apparatus 34 asindicated in the drawings; “longitudinal” also corresponds to thedirection of the length dimension (longest dimension) of web 10.

[0047] Inflation nozzle 38 comprises a gas outlet port 70 at distal end72 for injection of gas 74 into the inflatable chambers 16. A preferredgas is air, although other gases may suitably be employed such as, e.g.,CO₂, N₂, etc. Gas 74 may be supplied by an air compressor 76 mounted onapparatus 34 as shown in FIG. 2, or from other sources such ascompressed gas cylinders, ‘plant air’ (compressed air from a fixed,centralized source), etc. Gas 74 may be delivered to inflation nozzle 38via an internal tube 78 that runs through housing 43 as shown. Tube 78may be coupled to nozzle 38 via mounting block 80, which is secured toplatform 60 as shown in FIGS. 5-6.

[0048] With particular reference to FIGS. 5-6, it may be seen thatinflation nozzle 38 is adapted to position gas outlet port 70 closelyadjacent to inflation ports 24 and intermittent seals 18. In thismanner, while conveying mechanism 36 conveys web 10 along its travelpath, inflation nozzle 38 moves continuously and longitudinally betweenflanges 30 and sequentially inflates chambers 16 by introducing gas 74into their respective inflation ports 24. Preferably, the position ofinflation nozzle 38 is relatively fixed while web 10 moveslongitudinally past the nozzle.

[0049] The positioning of gas outlet port 70 closely adjacent toinflation ports 24 may be achieved by adapting at least a portion ofinflation nozzle 38, preferably distal end 72, to move in response tomovement of web 10 past the nozzle. Additionally, distal end 72 of theinflation nozzle is preferably biased towards, i.e., urged against,inflation ports 24 and intermittent seals 18. Consequently, distal end72 is caused to move as a result of contact between the distal end andintermittent seals 18 as web 10 moves past inflation nozzle 38. Suchmovement of the distal end is essentially oscillatory. At the upper endof the oscillation, the inflation nozzle begins to inflate a chamber. Atthe lower end of the oscillation, the distal end of the nozzle, whichhas been pulled downwards towards the nip between cylinders 44 and 46(where the formation of longitudinal seal 52 begins), the distal enddisengages with the now-inflated chamber and rebounds upwards towardsthe next, adjacent chamber to be inflated.

[0050] The lower end of the oscillation is shown in FIG. 5, whereinchamber C1 has been fully inflated by gas 74 from inflation nozzle 38(C1 is an arbitrary designation of the chamber 16 with which inflationnozzle 38 is engaged in FIG. 5). At this point in the oscillation,chamber C1 disengages from the inflation nozzle by moving downwards andout of reach of distal end 72. Preferably, such point in the lower endof the oscillation of inflation nozzle 38 places distal end 72 andoutlet port 70 just above the nip between cylinders 44, 46. Thisadvantageously allows the chamber to achieve a high degree of inflationby sealing the chamber closed just after it disengages with nozzle 38,i.e., when inflation port 24 of chamber C1 moves through the nip betweencylinders 44, 46 and is sealed by heating element 54 of sealing device40, which continuously creates longitudinal seal 52.

[0051] When chamber C1 disengages from inflation nozzle 38, the nozzlerebounds upwards until it is engaged by the inflation port 24 of thenext, adjacent chamber 16 to be inflated, which has been designated C2in FIGS. 5-6. In the meantime, chamber C1 has become an inflated chamber62 by virtue of being sealed closed by sealing device 40.

[0052]FIG. 6 shows the inflation nozzle at the upper end of itsoscillation, i.e., just after being engaged by chamber C2. As a resultof being biased towards inflation ports 24 and intermittent seals 18,the distal end 72 of the inflation nozzle extends into the inflationport 24 of chamber C2 as the nozzle begins to inflate such chamber. Thisadvantageously facilitates full inflation of the chambers by ensuringthat most of the gas 74 is injected into the chambers instead of beingblown back out between flanges 30. This is particularly important duringthe initial stage of inflating a chamber, when adhesion between sheets12, 14 can impede inflation. Further, by virtue of being movable, thedistal end of the nozzle remains in contact with the inflation port 24of chamber C2 as chamber C2 moves towards cylinders 44, 46 so thatoutlet port 70 remains in fluid communication with the chamberthroughout the oscillatory cycle of the nozzle. Such mobility of theinflation nozzle not only facilitates full inflation of the chambers,but it allows web 10 to be conveyed continuously, rather thanintermittently, through apparatus 34 as the chambers are sequentiallyinflated.

[0053] Inflation nozzle 38 is preferably in the form of a tube as shown,constructed from a relatively stiff but resilient material to allowmovement as described hereinabove. Preferred materials from which thenozzle may constructed include various polymeric materials, such asnylon, polyethylene, polypropylene, Teflon, etc. It is also preferredthat the distal end 72 be angled as shown in FIGS. 5-6 so that outletport 70 has an oval shape.

[0054] Other movable forms for inflation nozzle 38 are also possible,such as relatively rigid nozzles that move, e.g., pivotally,translationally, or rotationally, in response to movement of web 10 pastthe nozzle. As a further alternative, the inflation nozzle may beunmovable, i.e., have no movable components. In this instance, thenozzle may have a fin or wedge shape so that it and, specifically, theoutlet port thereof, can be placed as close as possible to the nipbetween cylinders 44, 46. Two or more outlet ports may be employed ifdesired.

[0055] Preferably, gas 74 is introduced by inflation nozzle 38 intochambers 16 at greater than atmospheric pressure ranging, e.g., fromabout 1 to about 25 psi above atmospheric pressure, more preferably fromabout 2 to about 10 psi. This may be achieved when compressor 76generates a gas pressure of about 5 to about 80 psi, more preferablyfrom about 10 to about 50 psi, and most preferably from about 15 toabout 35 psi. It is to be understood that the foregoing representpreferred ranges for the particular inflation nozzle 38 as illustrated,and that other gas pressures may be more suitable if other types ofinflation nozzles are employed. Further, the applied gas pressure frominflation nozzle may be adjusted as necessary to provide a desired levelof inflation/ness in inflated chambers 62.

[0056] Referring now to FIG. 7, the completed, i.e., inflated,cushioning material 64 may be seen, with a series of inflated chambers62, maintained in such inflated state by virtue of longitudinal seal 52,which seals closed each of the inflation ports 24.

[0057] With reference now to FIGS. 2 and 4, another feature of theinvention will be described. It has been found that the inflation ofchambers 16 may be facilitated by the additional step of effectingrelative movement between the opposing longitudinal edges of web 10,i.e., closed edge 32 and opposing edge 33 at which the open edges offlanges 30 terminate. Such relative movement decreases the distancebetween the longitudinal edges of the web as it is conveyed past theinflation nozzle during inflation. It has been found that thisadditional step can facilitate consistent and reliable inflation of thechambers. The decrease in distance can be accomplished by urging edge 33toward the closed longitudinal edge 32 such that a crease 81 forms atedge 32. Such creasing is believed to facilitate inflation of containers16 by making them more readily deformable as occurs during inflation,i.e., from an essentially two-dimensional shape prior to inflation to athree-dimensional shape as a result of inflation. Additionally, thecreasing or decrease in distance between the longitudinal edges may alsofacilitate fuller inflation of the web chambers.

[0058] Edge 33 may be urged toward closed longitudinal edge 32 bymounting platform 60 on housing 43 at an angle relative to the generallyvertical direction of closed longitudinal edge 32, i.e., relative to thedirection of travel of closed longitudinal edge 32 as web 10 is conveyedthrough apparatus 34. Such angle of platform 60 serves to direct edge 33towards closed longitudinal edge 32 as web 10 is conveyed past theplatform. Platform 60 may have any desired angle ranging, e.g., between0° and 90°, with 0° being vertical (or parallel to the direction inwhich longitudinal edges 32, 33 would otherwise extend from supply roll48 but for the diversion in direction caused by platform 60) and 90°being horizontal (or perpendicular to the direction in whichlongitudinal edges 32, 33 would otherwise extend from supply roll 48).Preferably, the angle of platform 60 ranges between about 10 and about20° and, more preferably, between about 1° and 10°.

[0059] In addition or alternatively, counter-rotatable cylinders 44, 46may be oriented at an angle with respect to the generally verticaldirection of closed longitudinal edge 32. As shown, the cylinders 44, 46may be angled by mounting them on angled platform 60. Preferably,inflation nozzle 38 is positioned immediately upstream of cylinders 44,46 as also shown. It has been found that the positioning of thecylinders at an angle immediately downstream of the inflation nozzleprovides the desired urging of the flange edge 33 toward the closed edge32 in that section of the web being conveyed past the inflation nozzle,thereby providing the desired improvement in inflation consistency andreliability.

[0060] Further details concerning the angling of the counter-rotatabledrive system is disclosed in commonly assigned, copending U.S.application Ser. No. 09/782,766, entitled “Apparatus And Method forForming Inflated Containers”, filed Feb. 13, 2001, the disclosure ofwhich is incorporated herein by reference.

[0061] A further aspect of the invention concerns the tension in web 10.At least some tension in the web is beneficial in that tension has, ingeneral, been found to provide better tracking of the web through theapparatus. For example, if the tension on the web is too low it maytravel out of the nip between cylinders 44, 46 or disengage frominflation nozzle 38. In addition, tension facilitates close slidablecontact between flanges 30 and inflation nozzle 38, which generallyresults in better concentration of the gas flow 74 into the inflationports 24 of chambers 16. Too much tension would be undesirable, however,because this may prevent or impede inflation of chambers 16.

[0062] In many instances, the resistance to rotation of supply roll 48and the frictional resistance caused by the movement of web 10 overguide roll 51 provides sufficient counter-resistance to the movementinduced by cylinders 44, 46 to result in a desired tensioning of web 10.In other cases, however, it may desirable to include in apparatus 34 adevice 82 for controlling the tension in the longitudinal flanges 30 toachieve a consistent and desired amount of tension. Such a device isbest illustrated in FIGS. 2-3, and includes a frictional member 84 thatis frictionally engageable with supply roll 48, i.e., capable ofapplying to supply roll 48 a frictional force that opposes the rotationof the supply roll. Frictional member 84 may take the form of a band,wire, or arm that is biased against supply roll 48, or any other elementthat acts as a brake against the rotation of supply roll 48. Thefrictional member may be frictionally engageable with supply roll 48either directly or indirectly, i.e., it may contact the supply rolldirectly or may contact an auxiliary component that is associated withthe supply roll and rotationally coupled thereto, such as friction wheel86 as shown. Thus, frictional member 84 may be frictionally engaged withfriction wheel 86, which is, in turn, rotationally coupled to supplyroll 48 such that supply roll 48 cannot rotate on shaft 42 without alsocausing friction wheel 86 to rotate. Frictional member 84 thus acts as abrake or drag against the rotation of friction wheel 86, and thereforealso against the rotation of supply roll 48, particularly when aweighted object is suspended from the frictional member or thefrictional member 84 is otherwise biased away from friction wheel 86,e.g., with a spring, in order to increase the frictional force appliedagainst the wheel 86 by frictional member 84.

[0063] Preferably, the tension-control device 82 also includes somemeans for varying the frictional force applied to supply roll 48 by thefrictional member 84 in response to changes in the tension in web 10.Such means may include a movable support plate 88, which preferablyforms the outer surface of platform 60 and has mounted thereto thecylinders 44 and 46, sealing device 40 and inflation nozzle 38 as shown.Movable plate 88 preferably is movable towards and away from supply roll48, and also is attached to friction member 84, e.g., via hook 90.Movable plate 88 may be mounted to the base 91 of platform 60 with apair of retaining pins 92, which pass through slots 94 in the movableplate and are attached to base 91 as shown. Slots 94 are shaped to allowmovable plate to move both towards and away from supply roll 48.

[0064] Movement of the movable plate 88 towards supply roll 48 causes adecrease in the frictional force applied to the supply roll byfrictional member 84. That is, the movable plate 88 with cylinders 44,46 mounted thereon has a weight ranging from, e.g., about 1-10 pounds,and is suspended from friction member 84 via hook 90. This weight thuscauses frictional member 84 to exert a frictional force against therotation of friction wheel 86 and, coupled thereto, supply roll 48. Whenthe plate 88 is caused to move towards supply roll 48, the amount offrictional force against the rotation of the supply roll decreases. Forreasons which are more fully explained in the above-incorporated U.S.application Ser. No. 09/782,766, this arrangement decreases variation inthe tension in web 10 that is otherwise caused by the variable forcerequired to withdraw web 10 from supply roll 48 as the web supply on theroll, and therefore the diameter thereof, decreases.

[0065] The foregoing description of preferred embodiments of theinvention has been presented for purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise form disclosed, and modifications andvariations are possible in light of the above teachings or may beacquired from practice of the invention.

What is claimed is:
 1. An inflatable web comprising: a) two sheetshaving inner surfaces sealed to each other in a pattern defining aseries of inflatable chambers of predetermined length, each of thechambers having at least one change in width over their length; b) aninflation port located at a proximal end of each chamber, said inflationports being formed by intermittent seals between said sheets; and c)longitudinal flanges formed by a portion of each of said sheets thatextend beyond said inflation ports and intermittent seals.
 2. Theinflatable web of claim 1, wherein said chambers comprise at least twoinflatable sections of relatively large width connected by relativelynarrow inflatable passageways.
 3. The inflatable web of claim 2, whereinsaid inflation ports are narrower in width than the inflatable sectionsof relatively large width.
 4. The inflatable web of claim 1, whereineach of said sheets comprises a heat-sealable thermoplastic polymer onits inner surface.
 5. The inflatable web of claim 2, wherein thesections of relatively large width are circular and capable of formingessentially spherical or hemispherical bubbles when inflated.
 6. Theinflatable web of claim 1, wherein said pattern defining the inflatablechambers form uninflatable planar regions between the inflatablechambers.
 7. The inflatable web of claim 1, wherein said flanges have awidth of at least ¼ inch.
 8. The inflatable web of claim 1, wherein saidflanges are substantially equal in width.
 9. The inflatable web of claim1, wherein each of said inflatable chambers has a closed distal endopposite from the proximal end of each chamber.
 10. The inflatable webof claim 1, wherein said inflation ports comprise inner surfaces thatare heat sealable to one another.
 11. A method of forming an inflatedcushioning product, the method comprising: a) providing an inflatableweb which comprises (1) two sheets having inner surfaces sealed to eachother in a pattern defining a series of inflatable chambers ofpredetermined length, each of the chambers having at least one change inwidth over their length, (2) an inflation port located at an end of eachchamber, said inflation ports being formed by intermittent seals in saidsheets, and (3) longitudinal flanges formed by a portion of each of saidsheets that extend beyond said inflation ports and intermittent seals;b) placing an inflation nozzle between the longitudinal flanges, thenozzle comprising a gas outlet port for injection of gas into theinflatable chambers; c) moving the web and inflation nozzle relative toeach other so as to cause the inflation nozzle to move longitudinallybetween the flanges; d) inflating the series of chambers sequentially bythe introduction of a gas into their respective inflation ports; and e)sealing the inflation port of each inflated chamber.
 12. The method ofclaim 11, wherein said web has opposing first and second longitudinaledges spaced by a predetermined distance, said longitudinal flangeslocated at said first longitudinal edge; and said method furthercomprises effecting relative movement between said first and secondlongitudinal edges to decrease the distance therebetween duringinflation.
 13. The method of claim 12, wherein said first longitudinaledge is urged towards said second longitudinal edge such that a creaseforms at said second longitudinal edge.
 14. The method of claim 11,wherein said longitudinal flanges are tensioned to cause close slidablecontact between said flanges and said inflation nozzle.
 15. The methodof claim 11, wherein said web is moved longitudinally past saidinflation nozzle.
 16. The method of claim 15, wherein at least a portionof said inflation nozzle moves as said web moves past said nozzle. 17.The method of claim 16, wherein said inflation nozzle has a distal endthat moves in response to movement of said web past said nozzle.
 18. Themethod of claim 17, wherein said movement of said distal end is causedby contact between said distal end and said intermittent seals formingthe inflation ports of each chamber as said web moves past saidinflation nozzle.
 19. The method of claim 11, wherein air is introducedby the inflation nozzle into the inflation ports at greater thanatmospheric pressure.
 20. The method of claim 15, wherein the inflationports are heat sealed after inflation by moving said web through a heatsealing station positioned immediately downstream from the inflationnozzle.
 21. An apparatus for inflating a web, comprising: a) a mechanismfor conveying an inflatable web along a path of travel, the webcomprising (1) two sheets having inner surfaces sealed to each other ina pattern defining a series of inflatable chambers of predeterminedlength, each of the chambers having at least one change in width overtheir length, (2) an inflation port located at a proximal end of eachchamber, said inflation ports being formed by intermittent seals betweensaid sheets, and (3) longitudinal flanges formed by a portion of each ofsaid sheets that extend beyond said inflation ports and intermittentseals; b) an inflation nozzle within said travel path and positioned forplacement between the longitudinal flanges of the web, said inflationnozzle comprising a gas outlet port for injection of gas into theinflatable chambers and being adapted to position said gas outlet portclosely adjacent to the inflation ports and intermittent seals so that,as said conveying mechanism conveys the web along said travel path, saidinflation nozzle moves longitudinally between the flanges to inflate theseries of chambers sequentially by the introduction of gas into theirrespective inflation ports; and c) a device for sealing the inflationports.
 22. The apparatus of claim 21, wherein at least a portion of saidinflation nozzle is adapted to move as said web moves past said nozzle.23. The apparatus of claim 22, wherein said inflation nozzle comprises adistal end that includes said gas outlet port, said distal end beingadapted to move in response to movement of said web past said nozzle.24. The apparatus of claim 23, wherein said distal end of said inflationnozzle is biased towards said inflation ports and intermittent seals.25. The apparatus of claim 24, wherein said movement of said distal endis caused by contact between said distal end and said intermittent sealsas said web moves past said inflation nozzle.
 26. The apparatus of claim21, wherein said web has opposing first and second longitudinal edgesspaced by a predetermined distance, said longitudinal flanges located atsaid first longitudinal edge; and said apparatus further comprises meansfor effecting relative movement between said first and secondlongitudinal edges to decrease the distance therebetween duringinflation.
 27. The apparatus of claim 26, wherein said means foreffecting relative movement comprises urging said first longitudinaledge towards said second longitudinal edge such that a crease forms atsaid second longitudinal edge.
 28. The apparatus of claim 27, whereinsaid means for effective relative movement comprises a platformpositioned at an angle, relative to said second longitudinal edge, whichdirects said first longitudinal edge towards said second longitudinaledge as said inflatable web is conveyed along said travel path.
 29. Theapparatus of claim 28, wherein a. said conveying mechanism includes apair of adjacent, counter-rotatable cylinders capable of engaging andmoving said inflatable web along said travel path; and b. said pair ofcylinders are mounted on said angled platform.
 30. The apparatus ofclaim 29, wherein said inflation nozzle is positioned immediatelyupstream of said cylinders.
 31. The apparatus of claim 21, furtherincluding a device for controlling tension in said longitudinal flanges.32. The apparatus of claim 21, wherein said sealing device is positionedimmediately downstream from the inflation nozzle.
 33. The inflatable webof claim 1, further including one or more lines of weakness that allowsections of said web to be removed.